A new imaging-plate X-ray diffractometer of the Weissenberg-camera type with an ad-justable multilayer-line screen system (IPD-WAS) has been developed. Prior to data collection, IPD-WAS automatically aligns an axis of a sample crystal and sets the multilayer-line (MLL) screens. For Weissenberg photography, IPD-WAS system uses two cylindrical imaging plates (IPs) . The IPs are read by a rotary readout mechanism. Owing to the good performance of the adjustable MLL screen system and the rotary readout mechanism, IPD-WAS achieves a data acquisition time of about one hour with reflection data of sufficient quality, which is suitable for time-resolved X-ray crystallography. IPD-WAS also enables faster crystal structure determinations of small molecules, including unstable crystals.
The mixed-valence Cu salt of DMe-DCNQI provides unique physical properties due to the interaction between the one-dimensional (1D) organic pπ band and the d-orbital of Cu ion. This system is metallic down to very low temperature at ambient pressure in spite of the 1D column structure, whereas the system exhibits a sharp metal-insulator (M-I) transition accompanied by a threefold superstructure under pressure. Reentrant behavior (M-I-M transition) is observed in the boundary pressure region. The selective dueteration of (DMe-DCNQI) 2Cu has enabled to control the chemical pressure. Application of this technique produces the Petf-T phase diagram of this system under ambient pressure. The effect of (chemical) pressure on these transitions in the system is generally understood from the change in charge transfer amount from metal ions to DCNQI molecules by low temperature crystal structure analysis and a doping method.
In the oxides with derivative structure of perovskite, peculier five-fold coordinated sites occur at the boundary regions between the fundamental structure units. The five-fold coordinated trigonal bipyramidal sites with large distortion have the much longer mean bond distances than those expected from the effective ionic radius and the distances are similar to those of octahedral site. The bond valence calculation for those sites yields significant lower-valences than the expected values due to the longer bond distances.
Atomistic visualization of behavior of internal crystalline boundaries, such as grain boundaries and interfaces, was realized by time-resolved high-resolution transmission electron microscopy at a spatial resolution of 0.1 nm and a time resolution of 1/60 s. Various types of atomic processes in mechanical interaction including approach, contact, bonding deformation and fracture, grain boundary migration, and interface formation in gas-phase epitaxial growth, were demonstrated in this review.
The crystal structures of ultra-thin organic crystals were examined by electron diffraction method using high voltage electron microscope and imaging plate system. High voltage electron microscope reduces the dynamical scattering effect in diffraction intensities and expedient in realizing flat Ewald sphere. Imaging plate has advantages of high sensitivity, wide dynamic range and good linear response for electron dosage compared to the conventional electron microscopic films and is useful to measure electron diffraction intensities. Using the system, it was shown that the electron diffraction method was applicable to analyze the crystal structures of thin films or micro-crystals at atomic level resolution.